The 32-year-old Federer is the most successful player to compete at the Barclays ATP World Tour Finals, compiling a 42-9 record and winning the title in 2003-04, 2006-07 and 2010-11. He finished runner-up to Novak Djokovic in last year’s final. The Basel native has qualified for the 12th consecutive year, tying Ivan Lendl for the most successive appearances at the season finale. Andre Agassi holds the record for most non-consecutive appearances (14).

“[It's] the absolute pinnacle of our sport," Federer recently said of the tournament. "You want to be able to showcase your talents against the best, with the biggest rivalries, in one of the coolest arenas in the world in front of amazing fans. For me it’s always been an honour to play there and I look forward to returning this year.”

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Federer opened his 2013 campaign with a semi-final showing at the Australian Open and in doing so became the first man to record 250 Grand Slam match wins. At Roland Garros he became just the fourth player in ATP World Tour history to record 900 match wins en route to reaching his 36th successive Grand Slam quarter-final.

Having finished runner-up to Nadal in the Internazional BNL d’Italia final in Rome in May, Federer won his first title of the season in June at the Gerry Weber Open in Halle, defeating Mikhail Youzhny. Federer also finished runner-up to del Potro in the Swiss Indoors Basel final on Sunday.

Tournament Director, Andre Silva, said, "As a six-time champion Roger stands alone as the most decorated player in the history of the Barclays ATP World Tour Finals. He is enormously popular here in London, where he has also won seven Wimbledon titles, and we’re delighted to welcome him back to The O2."

The Emirates ATP Race To London comes to a thrilling climax at this week’s BNP Paribas Masters in Paris-Bercy. Two singles and three doubles team berths remain up for grabs. Stanislas Wawrinka and Richard Gasquet currently hold the last two spots, but Milos Raonic is still in contention.